FOLR1 and adenocarcinoma: The FRα is also overexpressed in a wide variety of malignancies, with some studies citing about 40% of malignant lesions [5], such as ovarian cancer, invasive pulmonary adenocarcinoma, and adenocarcinoma spectrum lesions in the lung (Figure 1) [11,12,13,14,15,16,17,18,19,20,21,22].